After screening visit patients were booked for arthroscopy and had their cells harvesting from healthy cartilage. After the arthroscopy the patients were randomised in one of the three dose-groups. The cells are cultivated for 8-10 weeks in vitro to develope 3-dimensional spheroids, that are transplanted in an open knee procedure (treatment surgery)into the defect. Patients of all dose groups subsequently followed the same rehabilitation program and had post-surgery visits. The 12-month-visit is defined as final assessment. Then patients have follow-up assessments up to 60 months.